What Sustains Earth's Magnetic Field? Scientists Find The Answer

Posted: Jun 2 2016, 10:19am CDT | by , Updated: Jun 2 2016, 9:51pm CDT, in News | Latest Science News


What Sustains Earth's Magnetic Field? Scientists Find the Answer
Illustration of how the diamond anvil cell is used to mimic and study extreme Earth's core conditions. Credit: Stewart McWilliams

Scientists have found what keeps our planet's magnetic field running.

Earth’s magnetic field is a massive shield which protects humans from the charged particles and deadly radiations released from the Sun. The magnetic field has been around since at least 3.4 billion years and without it, it was not possible for life to thrive and survive on Earth.

Magnetic field of our planet is believed to be generated deep down in the Earth’s core with the rapid motion of liquid iron known as geodynamo and it is similar to the magnetic field generated by a bar magnet. Though scientists have been able to work out its likely structure but the origin of the magnetic field is not fully understood. How has Earth been able to sustain this massive shield throughout its history, it always remained a mystery to scientists. 

Our Earth is made up of three layers: core, mantle and crust. The inner core contains solid iron while the outer core is a liquid iron alloy that produces magnetic field but nobody has ever taken the journey to the core of the Earth to see it up close. The phenomenon exists under very extreme conditions, both very high temperatures and very intense pressures which is impossible to access.

“We sensed a pressing need for direct thermal conductivity measurements of core materials under conditions relevant to the core,” said lead researcher Alexander Goncharov from Carnegie Institution for Science. “Because, of course, it is impossible for us to reach anywhere close to Earth’s core and take samples for ourselves.”

To solve this problem, researchers used a tool called a laser-heated diamond anvil cell to replicate the conditions of Earth’s core and studied how iron reacts to those conditions.

Diamond anvil cell is an especially designed device that compresses tiny samples of materials in between two diamonds and heats them simultaneously with infrared lasers, creating the extreme conditions of deep Earth in the lab.  

For the latest study, researchers squeezed a thin foil of iron in the diamond anvil cell and mimicked the conditions of planetary interiors. Then, they studied how iron disseminates heat.

“We found very low values of thermal conductivity, about 18 to 44 Watts per meter per Kelvin, which can resolve the paradox and make the geodynamo operable since the early ages of the Earth.” Goncharov said.

These findings will add to scientists understanding of geodynamo paradox that has puzzled them over the years and may pave the way for improved techniques to unlock the mystery hidden in the core of the Earth.

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Hira Bashir covers daily affairs around the world.




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